The present disclosure relates generally to an apparatus and method for self-tuning a processing system in order to improve the efficiency of resource utilization, such as energy consumption, of the processing system.
A processing system used in manufacturing semiconductor devices typically includes, among other things, a process tool, vacuum pump, and abatement device. The process tool provides a process chamber in which a semiconductor wafer is processed into a predetermined structure. For example, a chemical vapor deposition can be performed to form an oxide layer on the semiconductor wafer in the process chamber. In another example, the process tool can include a process chamber in which the oxide layer is further etched into a predetermined pattern. In operation, the process chamber needs to be in a vacuum condition to ensure that the semiconductor process steps are not compromised by the presence of unwanted chemicals or impurities.
The vacuum pump is used to evacuate the process chamber to bring it to a desired vacuum condition. Depending on process requirements, one or more vacuum pumps can be selectively connected in series. For example, a booster pump and a backing pump that operate at different pressure levels can be connected in series to achieve a desired pumping performance. Regardless of the number of vacuum pumps being used, an inlet of the pump or assembly of pumps is connected to the process chamber, such that gases can be evacuated from the process chamber.
In a typical processing system, an outlet of the pump or assembly of pumps can be connected to an abatement device, which treats the hazardous exhaust gases evacuated from the process chamber before releasing them to the environment. For example, the abatement device can be a wet scrubber that uses water to absorb gaseous ammonia evacuated from the process chamber in a metalorganic chemical vapor deposition process. In another example, the abatement device can be a combustion-based apparatus in which the gaseous ammonia is decomposed by reacting with gaseous hydrogen.
It is desired to manage and reduce the resources, such as electric power, fuel, and water, consumed by the vacuum pump and abatement device during the semiconductor manufacturing processes. The power consumed by the vacuum pumps and abatement devices represents a significant portion of the total power consumed by the processing systems in manufacturing semiconductor wafers. Many efforts have been made in the semiconductor industry to improve the efficiency of resource utilization of the vacuum pumps and abatement devices, in order to reduce the manufacturing costs of semiconductor wafers.
One conventional method for improving the resource utilization efficiency is to put the vacuum pump and abatement device in an idle mode, when the process tool does not require that the vacuum pump and abatement device operate in their normal capacity. For example, when semiconductor wafers are being transferred into or out of the process chamber, the vacuum pump and abatement device can be put in the idle mode, in which they consume fewer resources than they do in a normal operation, without affecting the throughput. When the process tool requires the vacuum pump and abatement device to operate in their normal capacity, they can be brought back to their normal operation mode from the idle mode. Thus, resource saving is achieved without compromising on the performance and throughput of the process tool.
The idle mode can be referred to as the sleep mode, green mode, hibernation, reduced/low power mode, by different people in various contexts. It is noted that in this disclosure, idle mode is used to refer to all these modes in the meaning as discussed above.
One drawback of the conventional method is its inability to accurately control the timing for the vacuum pump and/or abatement device to recover from the idle mode. For example, the recovery time for the temperature of the vacuum pump to increase from that at an idle speed to a normal speed can be longer than the notice period given by the process tool, thereby resulting in delays to the start of the process and underutilization of the process tool. Another drawback of the conventional method is its inflexibility to adapt to changing conditions of the process system. For example, in the conventional method, the recovery time of the vacuum pump is initially set at a predetermined value, which is close to the actual time needed for the vacuum pump to recover from the idle mode to the normal operation mode. However, after many cycles of operation, there might be a loss in performance of the vacuum system, and therefore the time needed for the vacuum pump to recover from the idle mode to the normal operation mode becomes longer than the initially set value. Since the conventional method cannot adapt to the changing conditions of the processing system, the preset recovery time might become inaccurate over time.
As such, what is needed is a method and apparatus for adjusting the recovery time of a processing system in accommodation with the changing conditions of the processing system to improve the resource utilization efficiency of the processing system.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.